Question

Which one is the largest unicellular organism?
(a) Planaria
(b) Volvox
(c) Blue-green algae
(d) Yeast
(e) Acetabularia

Answer 1

Of all these, the largest unicellular organism has a complex shape that makes it an excellent model organism for research in cell biology.

Complete answer:
a) Acetabularia : It is one of the genera of species present in the subtropical waters that belong to green algae. These are single-sided species with a large, complex structure and scale. The extraordinary scale of 3-5 cm approaches this unicellular organism. It is one of the largest unicellular organisms.
b) Planaria : It is a multicellular organism that has a high potential for regeneration. These species replicate sexually as well as asexually.
c) Volvox : It belongs to the community of algae that form the boundary between species that are multicellular and colonial. In colonies, these species survive. Their colony consists of multiple photosynthetic Volvox units that are clustered together in a hollow sphere (up to 1000-3000 units). Thus, they are known to be multicellular in a broad sense.
d) Blue-green algae: They are also known as cyanobacteria. They are photosynthetic and marine. Most are usually unicellular, but they occur in colonies as well.
e) Yeast: Yeasts are eukaryotic fungi that belong to the kingdom Fungi. In nature, they are unicellular, but their size varies greatly, depending on the species and the climate, while some yeasts can grow to 40 um in size, they can vary from measuring 3-4 um in diameter.
So, the correct option is E.

Note: There are three fundamental components of Acetabularia : rhizoids, the median stalk and the apex. Rhizoids are short root appendages holding the nucleus and anchoring the substrate to the cell. Most of the length accounts for the median stalk and its apex is the position where the shape of the cap is shaped.